About 120,000 Web sites in Japan were subject to attacks by computer hackers or computer viruses in the April-June quarter, more than twice the number in the previous three months, the National Police Agency said Thursday.
The attacks, aimed at changing or destroying computer data in the targeted Web sites, averaged about 1,300 a day. The NPA said no actual damage was reported.
The United States topped the list of countries from which these attacks were last tracked, at 34.7 percent, followed by the Netherlands at 20.3 percent and China at 12 percent. The agency said the number of attacks traced to the Netherlands showed a sharp increase.
The NPA said 53.9 percent of the cyber attacks in the April-June period were attributable to the Slammer Worm, the computer virus that caused extensive connection problems around the world in January, especially in South Korea.
Attacks in the form of Port Scan, in which hackers try to detect programs operating in the targeted computers, accounted for 37.9 percent to the total.